Answer
The issue should not be viewed merely in terms of individual ritviks.
The real question is whether there is an institution behind the system.
If someone independently leaves and declares himself a ritvik without any institutional structure, that lacks sanctity and accountability.
The proper model is institutional. There should be temples, temple presidents, congregations, and a governing structure. Devotees who subscribe to the same principles should work together.
For example, if several temples and groups cooperate, their devotees can collectively participate in selecting and confirming leadership. This can be done through a referendum-like process.
A referendum is often used in times of institutional crisis. If established leadership loses credibility or begins violating foundational principles, the broader body of members may participate in creating a new system of representation and governance.
The same principle can apply here.
In an emergency situation, devotees may organize themselves according to Srila Prabhupada's instructions and establish governing structures that oversee institutional activities.
There is no objection to multiple ritvik groups existing. There may be one group, two groups, or many groups. The essential point is that each should create a functioning institution dedicated to expanding preaching.
What is important is not merely maintaining a single temple or a small following, but developing a structure capable of expanding Srila Prabhupada's mission.
Any number of institutions may exist while following the same basic ritvik principles, provided they are organized, accountable, and dedicated to preaching.
Srila Prabhupada himself demonstrated broad-mindedness in this regard. He acknowledged that there can be many branches of Lord Chaitanya's tree. Multiple organizations may exist, each engaged in spreading Krishna consciousness.
The key criterion is not organizational uniformity but sincere commitment to expanding the preaching mission according to Srila Prabhupada's instructions.